Network nodes of a network can be communicatively coupled to further network nodes of the network. Nodes that are communicatively coupled are able to exchange a message in any one of the two directions. A coupling of the nodes may be wireless or with wires. A node of the network may be directly coupled only to one or more neighboring nodes. However, the nodes may provide routing functionality that allows for routing of messages from a first node to a second node by traversing directly coupled nodes in between the first and second node.
The network may furthermore include a gateway node that can send a message from one of the nodes to an application device, for example an application program running on a computer system. The application device may receive the messages, analyze them, and report a result to an administrator of the network. The application device may further send control messages to control the network nodes. The gateway node receives such a control message, and the control message is then routed to the one or more nodes to which the control message is addressed.
The network nodes may be used for different purposes. For example, each network node may include a sensor unit. The sensor unit may also be an external device to which the node is coupled. The sensor unit may have a function of receiving specific signals that are reported to the application device by using the network nodes. The signals may be, for example, usable to measure a temperature of the environment. In a specific example, the sensor unit may be used for an exchange of a message between coupled nodes. In an example, the nodes may be configured to receive radio frequency signals. The nodes may include, for example, a reader of radio frequency identifier transponders which are within a specific distance. In the example, a node is configured to transmit radio frequency signals that are receivable by neighboring nodes, that is, coupled nodes. The radio frequency signals represent the message and the nodes can process the message, for example by initiating a transmission of the message in the form of radio frequency signals to further coupled nodes.
In a further example, the sensor unit may be a smoke detector. In the further example, the sensor unit is coupled to one node and via the one node the network is used for reporting a result of the smoke detector as a message to the application device. The nodes that are coupled to smoke detectors, for example, may exchange radio frequency signals which are not receivable by the smoke detectors.
The number of the sensor units and the nodes of the network may be large, that is, the network can be large. The number of the sensor units of a large building, for example, motion detectors, may be large and accordingly the number of the nodes is large in case that each sensor unit is coupled to one node of the network. An administration of the sensor units includes maintenance of the sensor units and of the nodes of the network and this is demanding for a large network.